Chuck



Sept. 10, 1929. c. M. coNRADsoN l$727,535

CHUCK Filed sept. 1s, 192e. 2 sheets-sheet 1 mi., 4f,

Illlilllllllll I f5 if A u En a i2'/ (fz Sept 10, 1929' c. M. coNRADsoN 1,727,535

CHUCK Filed Sept. 15, 1926 2 Sheets-Sheet 2 @WJ T' mt/MJL all Patented Sept. 10, 1929.

U N I T ED STA TIE S CONRAD M. CONRADSON, OF AY, WISCONSIN.

CHUCK.

Application lediSeptembe/r 13, 1926. Serial'fNo. 134,999.

This invention relates to chucks for holding work for machine tools such. as lathes, and has for its object the provision of a chuck having, a plurality of pairs of jaws which may be operated simultaneously and which will produce substantially equal clamping force on the object held by the chuck even though the object may be irregular in shape, the work being accurately centered by the jaws.

@ther objects will appear from the following description.

The invention is exemplified in the combination and arrangement of parts shown in the accompanying drawings and described in the following specicatiomand itis more particularly pointed out in the appended claims.

1n the drawings Fig. 1 is a face view of the chuck parts broken awayfto show the construction of the adjustment members Fig. 2 is a section on` line 2-2 of Fig. 1;

Fig. 3 is a section on line 8-8 4of Fig. 1;

Fig. 4 is a' section on line 4 4 ofv Fig. 1;

Fig. 5 is a a View similar to Fig. 4 but showing a modified construction;

Fig. 6 is a fragmentary sectional View showing a different modification of gearing.

rlhe chuck comprises a Vdisc-shaped body portion 10 having slideways 117 12, 18 and 14, formed in the face thereof for receiving sliding jaws 15, 16, 17 and 18, respectively. The jaws are provided with flanges 19 which extend into undercut grooves at the sides of the slideways. Each of the jaws is provided with a T-slot 2O to which false jaws of any desired form may be secured. The discshaped body member 10 is provided with a central hollow cylindrical boss 21 upon which a scroll disc 22 is journaled, the disc being provided with spiral teeth 23 on the face thereof adjacent the jaw members. As shown in Fig. 4, the body 10 is provided with a face plate 24 and inwardly projecting webs 25 at each side of the jaw members, forming the guides for the jaw members. rlhe guides are open at their inner sides and the jaw members 16 and 18 are provided with rack teeth 26 which extend into the space kabout the yboss 21 and engage the spiral teeth on the fdise 22. Extending about the periphery of the scroll plate 22 is a second scroll plat-e 27 provided with spiral teeth 28 and, as shownin Fig. 2, the jaws 15 and 17 are provided with teeth 29 which mesh with the teeth 28 of the scrolly plate 27. It willy be apparent that rotation of the scroll 22 will move the pair of jaws 16 and 18 simultaneously toward. or away from each y other7 depending upon the'direction of rotation ofthe scroll and that likewise, rotation of the scroll 27-will operaterthe other pair of jaws and 17 f ina similar manner. A disc 30 is journaled ontheboss 21 in contact-withy the rearfaces yof the scrolls 22 and; 27 the rear face of the Ldisc l30 being provided with beveled gear teeth 31 adjacent the outer kperiphery of the disc. A cover plate 32 is secured yto the body.member`10 by cap screws 38 to hold the disc 30 in place On the boss 21. One or more pinions 34 are fjournalled in the ldisc 82 and the side wall of the body member 10 and mesh with the gear teeth 31, as shown in Fig. 4. The spindle o-f the pinion 34 is provided with anA angular socket 35wfor receiving a suit- `able-wrench to rotate the pinion. The gear -wlieel 3() carries a stud 36 onwhich a pinion 37 isqjournalled. The pinion meshes with spury gear teeth 88 on the scroll 22 and with internal spur gear teeth '39 on the scroll 27 W hen the pinion 34 is rotated to ydrive the gear wheel 30, the stud 3G `will carry the pinion 37 aboutthe boss 21 and so long as the jaw members move freely7 the scrolls 22 and 27 will move together andthe jaw members will all be fed uniformly toward the center of the chuck. If an irregular piece of work is disposed within the jaws7 one of the pairs of jaws :will engage the work prior to the other pairand further movement of the first pair of jaws will be arrested. This ywill prevent further rotation ofv one of the scrolls so that further movement `of the gear 30will cause the pinion 37 to rotate upon its stud shaft 86 and drive the second scroll at an increased rate of speed, thus feeding the second'pair of jaws inwardlyA until they are in engagement with the piece of work. When both pairs of jaws are in contact with the work, further rotation of the pinion 34 and gear'30 will tighten both pairs of jaws simultaneously against the Work although the work may be irregu lar in shape.

ln order thatthe pairs of jaws may not be unduly displaced relative to each other, the adjacent edges of the scrolls 22l and 27 are provided with registering grooves 40 and 41 respectively,"and a roller42 dis-Y iposed in these grooves, as shown in Figs. l -and 4, to limit the relative rotation ot the scrolls 22 and 27. the pinion 37 form an equalizing planetary gear system which tends to equalizer` the V'force exerted by the scrolls on the pairs or' jaws. Y

Owing to the slight difference in the pitch diameter of the gear teeth on the scrolls 22 ,and 27, there will be a slight diderence in the pressure exertedr on the two sets of aws. Itwill be understood that the term equalizing, as used in-r the specication and claims, is not restricted to a construction in' which the forces a-relmade exactly equal but applies to constructions suoli as that shown in Fig. 4, where the arrangement distributes` the force between the dierent pairs ot aws, tending to equalize these forces. ln ordinary practice, the slight difference yin pres sure, referred to above, is immaterial but it may be avoided by providing two pinions 43 and 44 journaled on the stud 36,' shown in Fig. 6. It the pinion 43 has the same ratio to the teeth ot the scroll 27 as that ot the pinion 44 to the teeth of the scroll 22, equal pressure will be exerted on the two set-s of jaws. AsV an example, the smaller pinion may have a pitch diameter ot 2.4 inches and mesh with teeth on the scroll 22 having a pitch diameterof 9.6 inches, giving a ratio of l tOf4. The other pinion 43 would then have a diameter ot 4 inches while the pitch diameter of the teeth on the scroll 27 would be 16. inches; Of course, other ratios may be used so long as the ratio ot each pinion tolits scroll is the same as the other pinion to its scroll;

ln the modification shown in Fig. 5, the inner scroll 22 is provided with a downwardly extending flange 45 to which a ring 46 is secured by screws 47. rlfhe outer edge of the ring 46 is provided with beveled gear teeth which inesliwith. one or more beveled pinions 48 which are journaled in flanges 49 and 50 carried on a beveled gear 5l which rotates about the flange 45 on the inner scroll 22. The beveled gear 51 is driven by one or more beveled pinions 52 j ournaled in the side flange ofthe body portion l0 and in bearing members extending upwardly fromr the cover plate 53. The outer scroll 27 is provided with a flange 54 which meshes with the pinion 48.. Itk will be apparent that The gears 38 and 39 and,

the pinion 48 operates on the saine radius for both scrolls so that equal forces will be exerted by both pairs of jaws with this arrangement.

l claim i lf. A work-holding chuck comprising a plurality of substantially coplanar pairs of j aws, means for closing the jaws of each pair simultaneously, and an equalizing drive interposed between the closing means for the said diierent coplan'ar Vpairs of jaws.

2. A work-holding chuck comprising a supporting block, two substantially coplanar pairsot diametrically opposed jaws mounted to slide in said supporting block, separate dr'ves for eachpair otl ja arranged to move the jaws o each pair simultaneously toward each other and a pressure equalizing connection between the drives ior said pairs of aws.

3. A work-holding Ychuck comprising a supporting block, two substantially coplanar pairs of opposed jaws mountet to slide toward each other 4in said block, separate drives torsaid pairs orn jaws, and a common operatingdevice for said dri r'es operating as an equalizer between said pairs ot jaws.

4. A work-holding chuck comprising a supporting block, two substantially coplanar pairs of jaws mounted to move radially in said block toward a common center, the directions of movement ofthe jaws of the two pairs being normal to each other, separate drives lor said jaws arranged to move the jaws of each pair at the saine rate toward said common center, and equalizing means for operating said drives to permit the jaws orp either pair to continue to move after the jaws or the other pair have engaged a piece of work. Y

5. A work-holding chuck comprising a supportingbloclr, a plurality or substantially coplanar pairs ot jaws slid-ably mounted in said block, a separate scroll. for operating the jaws of'each pair and pressure equalizing gearing interposed between said scrolls.

6. A work-holding chuck comprising a plurality of substantially coplanar pairs ot' jaws,separate drives for said pairs of jaws, and planet-ary gearing -connecting said f drives for equalizing the pressure exerted by said pairs or" jaws. 7. A work-herding chuck comprising a plurality of substantially coplanar pairs of jaws, a separate scroll for operating Vthe jaws ot' each pair, said scrolls being mounted for rotation independently ot each other and a planetary gear drive for said scrolls, 8. fr Vwork-holding chuck comprising a plurality ot substantially coplanar pairsot jaws, a separate scroll for driving the jaws of each pair, a rotary member having a pinion journalled thereon, and gear teeth formed on said scrolls and meshing with said pinion.

9. A work-holdingy chuck comprising a lill) support having a plurality of substantially coplanar pairs of jaws slidably mounted therein and movable toward and from a common center, concentrically disposed scroll plates for operating said jaws, the jaws of each pair having teeththereon meshing with a common scroll plate.

'10. A work-holding chuck comprising a supporting block having a plurality of substantially coplanar pairs of jaws slidably mounted therein, concentric scroll plates for operating said jaws, the jaws of each pair having teeth meshing with the teeth on a common scroll plate, and planetary gearing for driving` said scroll plates and for equalizing the pressure exerted by said scroll plates on said pairs of jaws.

ll. A work holding chuck comprising a supporting block, a plurality of substantially coplanar pairs of jaws slidably mounted in said block 'to move toward and away from a common center, a plurality of scroll plates mounted to rotate in said block, a gear wheel mounted to rotate concentrically with said scroll plates, a pinion mounted on said gear wheel and meshing with gear teeth on said scroll plates to form a planetary gear system for operating said scroll plates to drive said jaws and to equalize the pressure exerted by said jaws, means for limiting the relative displacement of said scroll plates, and a pinion accessible from the side of said chuck tor driving said gear system.

l2, A work-holding chuck comprising a supporting block, a plurality of pairs of jaws mounted to slide toward a common center on said block, a pair of concentric scroll plates mounted to rotate in said block about an aXis passing through said common center, teeth on the jaws of one of said pairs meshing with the inner one of said scroll plates, teeth on the jaws of another of said pairs meshing with the outer one of said scroll plates, a gear mounted to rotate about the axis of said scroll plates, a pinion journaled on said gear, -ear teeth on said scroll plates meshing with said pinion, and a beveled pinion for rotating said gear, said beveled pinion having a shaft iXed thereto and projecting from the side of said chuck to receive a tool for rotating said pinion and operating the jaws of said chuck.

In testimony whereof I have signed my name to this specification on this 9th day of September, A. D. 1926.

CONRAD M. CONRADSON. 

